Carburetor adjusting mechanism



July 24, 1956 DIETZ 2,755,818

CARBURETOR ADJUSTING MECHANISM Filed Dec. 18, 1953 2 Sheets-Sheet 1Robert A. 0/29)? INVENTOR.

WW 12m United States Patent CARBURETOR ADJUSTING MECHANISM Robert R.Dietz, Havertown, Pa.

Application December 18, 1953, Serial No. 398,994

3 Claims. (Cl. 137-'-637.3)

This invention relates generally to carburetors, and pertains moreparticularly to mechanism for ad usting the metering system ofcarburetors of the type shown In the patents to John R. Fish, Nos.2,214,273 and 2,236,595,

issued September 10, 1940, and April 1, 1941, respectively.

A primary object of this invention is to provide an improved form ofmetering adjustment mechanism for use in conjunction with carburetors ofthe type illustrated in the above mentioned patents, wherein themetering adjustment can be accomplished with a minimum of effort bymerely manipulating mechanism disposed exteriorly of the carburetorassembly.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

Figure l is a perspective view of a carburetor with portions thereofbroken away to show the operating mechanism;

Figure 2 is a side elevational view of a carburetor having the improvedattachment positioned thereof, portions of the attachment being brokenaway to show the relationship of parts;

Figure 3 is a vertical section taken through the carburetor assemblyshown in Figure 1 illustrating details of the attachment;

Figure 4 is a vertical section taken substantially along the plane ofsection line =%4 in Figure 3; and I Figure 5 is a sectional view showinga modified form of adjusting mechanism.

Referring now more particularly to the drawings, the carburetorillustrated includes a barrel portion having a mounting flange portion12 at its lower end for mounting the carburetor on an intake manifold ofan internal combustion engine. The upper end of the barrel is providedwith a collar 14 to which an air cleaner mechanism is conventionallysecured. A portion 36 of the carburetor body is removable from theremainder of the carburetor, a gasket 18 being provided therebetween,and this body portion forms the gasoline reservoir for the carburetor,suitable float and float valve mechanism being associated therewith, asis conventional. A fitting 20 is provided on the upper surface of thefloat chamber body, and a gasoline inlet line 22 is connected therewithin a manner well understood in the art.

Referring now more particularly to Figures 1 and 3, it will be notedthat the barrel 1! has a pair of diametrically opposed openings thereinreceiving the throttle shaft member 22, one end portion of whichprojects into the float chamber and has rigidly afiixed thereto an armmember 24 provided with a fuel passageway 26 opening at its lower endinto the fuel feed groove 28 on the side wall 30 of the carburetor. Theopposite end of the throttle shaft extends outwardly from the oppositeside of the barrel 10 and is provided thereon with an actuating armmember 32 connected by a suitable fitting member 34 to throttle2,755,818 Patented July 24, '5

linkage member 36 by means of which rotation of the throttle shaft iseffected by manipulation of the conven- "barrel ll), as is conventional,and this valve has diametrically opposed hub portions 42 and 44 receivedon a portion of the throttle shaft 22 and a sleeve member 46,respectively. Each of the hub portions 42 and 44 is provided with aradial aperture internally threaded to receive a setscrew member.Normally, in this type of carburetor, the sleeve member 46 isnon-existent, this sleeve forming a part of the present invention, andthe hub portions of the butterfly valve are rigidly affixed to thethrottle shaft 22 by means of setscrews received in the threadedapertures in the hub portions.

In the conventional carburetor structure, it is to be noted that thediameter of the throttle shaft 22 is greater than the width of thecentral web porion 48 of the butterlly valve 40 and that the throttleshaft is provided with a series of longitudinally spaced openings 50'which communicate with the upstream side 'of the barrel 10in the mannershown most clearly in Figures 1 and 4. In the conventional structure,when it is necessary to change the metering adjustment of the apertures50 to be more or less uncovered by the central web portion 48 of thebutterfly valve, it is necessary to remove the air cleaneron thecarburetor, loosen the setscrews and manually rotate the butterflyvalve. This method of adjusting the metering of the carburetor iscumbersome, since it necessitates the removal of the air cleaner andmanipulation of the setscrew members in the hub portions 42 and 44 ofthe throttle valve, and also manipulation of the throttle valve withrespect to the throttle shaft to effect the desired fuel setting.Additionally, this method does not lend itself readily to rapidadjustment since it is impractical to make the adjustment while theengine is running, so that it makes it take several trial adjustments ofthe assembly to effect the desired end result.

To overcome this cumbersome method of adjusting the metering system ofthe carburetor, the boss 52 on the carburetor barrel it) which isnormally apertured to journal the throttle shaft 22 is reamed out orotherwise enlarged to receive the previously mentioned sleeve 46 and thehub 4d of the throttle valve 49 is also reamed out to receive an innerend portion of this sleeve in the manner shown most clearly in Figure 3.One of the setscrew members 54 is then replaced in the hub 44 to rigidlyaffix the throttle valve it) to the sleeve 46, the other setscrew beingomitted in the hub portion 42 such that the butterfly valve is, ineffect, journaled on the throttle shaft 22. The sleeve 46 projectsoutwardly through the boss 52 and its outer end receives an arm member56 whose split upper end 58 surrounds the sleeve and is clampinglyengaged thereon by virtue of the clamping screw 66 extending through theears 62 at the upper end of the arm 56. The lower end of the arm isformed as a gear segment having the teeth 64 thereon, in the mannershown most clearly in Figures 1 and 2. A second arm member 66 has itssplit upper end 68 surrounding the throttle shaft 22 and clampinglyengaged thereon by virtue of the clamping screw 70 engaging through thecars 72 in a manner similar to the first mentioned arm. The lower end ofthis second arm is provided with the laterally projecting, spacedparallel leg members 74 which are positioned below the gear segmentteeth 64 and these legs are apertured to receive a shaft 76 to which theworm gear 78 is suitably feathered. One end portion of the shaft 76 isprovided with a hand wheel portion 80, and it is to be understood thatthe legs 74 normally frictionally engage on the shaft 76 to such anextent that the unit is self-locking. The worm gear 78, of course,meshes with the gear segment teeth 64 and it will be manifest that bymanipulation of the shaft 76 and consequently the worm gear 78, relativerotation between the throttle shaft 22 and the butterfly valve 40 willbe effected such as to change the amount the apertures 50 are covered oruncovered by the central portion 48 of the butterfly valve. Accordingly,it will be manifest that metering adjustment of the carburetor is thusefiected without removal of the air cleaner or any other associatedcarburetor mechanism, and that the adjustment may be effected veryrapidly and while the engine is running to produce the most accuratesetting of the metering holes 50.

Referring now more particularly to Figure 5, wherein a modified form ofadjusting mechanism is shown, it will be seen that in addition to thepreviously described adjusting mechanism, one of the end plugs 38 hasbeen removed from the throttle shaft 22 and this end portion of thethrottle shaft enlarged and internally threaded to receive the meteringneedle 82. The outer end of the metering needle is provided with a handwheel portion 84 and the inner end 86 is of reduced diametercorresponding to the internal diameter of the throttle shaft such thatmanipulation of the metering needle 82 may effect the blocking off ofone or more of the metering holes 50 in the throttle shaft, Figure 5illustrating a position in which all of the metering holes have beenblocked off. In this manner, a finer adjustment of the meteringmechanism may be effected than is otherwise produced by the provision ofthe previously described assembly alone.

From the foregoing, the construction and operation of the device will bereadily understood and further explanation is believed to beunnecessary. However, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction shown and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the appended claims.

What is claimed as new is as follows:

1. In a carburetor, a barrel, a throttle shaft projecting diametricallythrough said barrel and having one end journaled therein, a sleeverotatably received on said throttle shaft and journaling an intermediateportion thereof in said barrel, a butterfly valve disposed within saidbarrel having diametrically opposed hub portions receiving a portion ofsaid shaft and an inner end portion of said sleeve respectively, saidbutterfly valve being fixed to said sleeve, said throttle shaft beinghollow and having a plurality of apertures between the hub portions ofsaid of said barrel, a second arm fixed to said throttle shaft adjacentthe first arm, a gear segment formed on the free end of said first arm,a worm gear rotatably carried by the free end of said second arm in meshwith said segment, and means for rotating said worm shaft to effectrelative rotation between said throttle shaft and butterfly valve.

2. In a carburetor, a barrel, a throttle shaft projecting diametricallythrough said barrel and having one end journaled therein, a sleeverotatably received on said throttle shaft and journaling an intermediateportion thereof in said barrel, a butterfly valve disposed within saidbarrel having diametrically opposed hub portions receiving a portion ofsaid shaft and an inner end portion of said sleeve respectively, saidbutterfly valve being fixed to said sleeve, said throttle shaft beinghollow and having a plurality of apertures between the hub portions ofsaid butterfly valve, a first arm fixed to said sleeve externally ofsaid barrel, a gear segment formed on the free end of said first arm, asecond arm fixed to said throttle shaft adjacent the first arm, a pairof laterally extending spaced legs on the free end of said second arm, aworm gear rotatably received between said legs in mesh with saidsegment, and means for rotating said worm shaft to effect relativerotation between said throttle shaft and butterfly valve.

3. In a carburetor, a barrel, a throttle shaft projecting diametricallythrough said barrel and having one end journaled therein, a sleeverotatably received on said throttle shaft and journaling an intermediateportion thereof in said barrel, a butterfly valve disposed within saidbarrel having diametrically opposed hub portions receiving a portion ofsaid shaft and an inner end portion of said sleeve respectively, saidbutterfly valve being fixed to said sleeve, said throttle shaft beinghollow and having a plurality of apertures between the hub portions ofsaid butterfly valve, a first arm fixed to said sleeve externally ofsaid barrel, a second arm fixed to said throttle shaft adjacent thefirst arm, and means connecting said arms for effecting relativerotation between said throttle shaft and butterfly valve.

FOREIGN PATENTS 1 444,625 France 1912

